`inclusion`
  Warn about inclusions in element type declarations.
`exclusion`
  Warn about exclusions in element type declarations.
`rcdata-content`
  Warn about RCDATA declared content in element type declarations.
`cdata-content`
  Warn about CDATA declared content in element type declarations.
`ps-comment`
  Warn about comments in parameter separators.
`attlist-group-decl`
  Warn about name groups in attribute declarations.
`element-group-decl`
  Warn about name groups in element type declarations.
`pi-entity`
  Warn about PI entities.
`internal-sdata-entity`
  Warn about internal SDATA entities.
`internal-cdata-entity`
  Warn about internal CDATA entities.
`external-sdata-entity`
  Warn about external SDATA entities.
`external-cdata-entity`
  Warn about external CDATA entities.
`bracket-entity`
  Warn about bracketed text entities.
`data-atts`
  Warn about attribute definition list declarations for notations.
`missing-system-id`
  Warn about external identifiers without system identifiers.
`conref`
  Warn about content reference attributes.
`current`
  Warn about current attributes.
`nutoken-decl-value`
  Warn about attributes with a declared value of NUTOKEN or NUTOKENS.
`number-decl-value`
  Warn about attributes with a declared value of NUMBER or NUMBERS.
`name-decl-value`
  Warn about attributes with a declared value of NAME or NAMES.
`named-char-ref`
  Warn about named character references.
`refc`
  Warn about ommitted refc delimiters.
`temp-ms`
  Warn about TEMP marked sections.
`rcdata-ms`
  Warn about RCDATA marked sections.
`instance-include-ms`
  Warn about INCLUDE marked sections in the document instance.
`instance-ignore-ms`
  Warn about IGNORE marked sections in the document instance.
`and-group`
  Warn about AND connectors in model groups.
`rank`
  Warn about ranked elements.
`empty-comment-decl`
  Warn about empty comment declarations.
`att-value-not-literal`
  Warn about attribute values which are not literals.
`missing-att-name`
  Warn about ommitted attribute names in start tags.
`comment-decl-s`
  Warn about spaces before the MDC in comment declarations.
`comment-decl-multiple`
  Warn about comment declarations containing multiple comments.
`missing-status-keyword`
  Warn about marked sections without a status keyword.
`multiple-status-keyword`
  Warn about marked sections with multiple status keywords.
`instance-param-entity`
  Warn about parameter entities in the document instance.
`min-param`
  Warn about minimization parameters in element type declarations.
`mixed-content-xml`
  Warn about cases of mixed content which are not allowed in XML.
`name-group-not-or`
  Warn about name groups with a connector different from OR.
`pi-missing-name`
  Warn about processing instructions which don't start with a name.
`instance-status-keyword-s`
  Warn about spaces between DSO and status keyword in marked sections.
`external-data-entity-ref`
  Warn about references to external data entities in the content.
`att-value-external-entity-ref`
  Warn about references to external data entities in attribute values.
`data-delim`
  Warn about occurances of `<' and `&' as data.
`explicit-sgml-decl`
  Warn about an explicit SGML declaration.
`internal-subset-ms`
  Warn about marked sections in the internal subset.
`default-entity`
  Warn about a default entity declaration.
`non-sgml-char-ref`
  Warn about numeric character references to non-SGML characters.
`internal-subset-ps-param-entity`
  Warn about parameter entity references in parameter separators in the internal subset.
`internal-subset-ts-param-entity`
  Warn about parameter entity references in token separators in the internal subset.
`internal-subset-literal-param-entity`
  Warn about parameter entity references in parameter literals in the internal subset.